1. Field of the Invention
This invention relates generally to a single-use, disposable, multi-film delivery system for multi-component tooth whitening, desensitization and remineralization, which comprises an orally dissolvable film (ODF) and an undissolvable plastic or polymer film, the compositions on the films chemically activate to rapidly accelerate the tooth whitening, desensitizing and/or remineralizing effects. More particularly, the present invention relates to a first orally dissolvable film having a peroxide activation complex and desensitizing agents and/or remineralizing agents and/or anti-inflammatory agents and a polymer system for a controlled dissolution by interaction with the fluid or liquid contained in the whitening composition on the second undissolvable film, the said whitening composition also contains stabilizers and thickening agents. Even more particularly, the present invention relates to multi-film delivery systems that are thin, transparent, comfortable and inconspicuous when worn. This invention relates to methods of making such tooth whitening products, more particularly the methods of making the orally dissolvable film (ODF).
2. The Prior Art
A tooth is comprised of an inner dentin layer, and outer enamel layer coated with a protective layer called dental pellicle, which is a protein film that forms on the surface of enamel. The dental pellicle and the enamel can become extrinsically stained or discolored over time because the enamel layer of a tooth is porous, meaning that any substances such as coffee, red wine, tobacco, tea and foods that are rich in dark pigment can easily be absorbed within the pores, and accumulate on the enamel layer of the tooth and form a pellicle film over the teeth. Frequently eating these particular foods can cause stains and permanent discoloration of teeth.
There are several single-film based tooth whitening patches and strips, both in dissolvable and undissolvable forms, for home use available in the marketplace today. Their peroxygen concentrations range from 3-14% by weight. However, these compositions are considered to have a slow bleaching effect. These strips have the drawback of not chemically activating, and thus not efficiently whitening teeth and requiring users to wear for extended periods of time, usually 30 minutes or more. If the user chooses to wear for a short amount of time, the peroxygen contained on the whitening strips will not have enough time to breakdown into bleaching radicals and trigger the whitening effect. However, long wear times for whitening treatments often cause or are accompanied by sensitivity and/or demineralization of teeth, and hence separate desensitizing or remineralizing treatment is often needed afterward.
Peroxygen compounds have been used for many years in tooth whitening because the decomposition of these compounds produces free radicals that oxidize the colored organic molecules and inorganic compounds. Peroxygen compounds, for example, hydrogen peroxide, on their own are relatively weak oxidants under mild conditions: they can achieve some oxidations unaided, but for truly effective applications, it requires activation in one way or another.
The decomposition of hydrogen peroxide has been widely studied as a model reaction for its catalytic activity of various metal complexes and has also been studied as a catalase model. It has been known for about a century that the decomposition of H2O2 to H2O and O2 is drastically accelerated by a few different factors. The rate of hydrogen peroxide decomposition increases with rising temperature, concentration and pH. Decomposition is catalyzed by various compounds, including most transition metals and their compounds (e.g. manganese dioxide, silver, and platinum). Certain metal ions, such as Fe2+ or Ti3+, can cause the decomposition to take a different path, with free radicals such as (HO.) and (HOO.) being formed. Non-metallic catalysts include potassium iodide, which reacts particularly rapidly. Hydrogen peroxide can also be decomposed biologically by enzyme catalase.
In one aspect, the present invention is based upon the discovery that when a peroxide containing component and peroxide activating agents such as transitional metal salts or complexes, enzymes, electrolytes, alkaline, and mixtures thereof, which are normally incompatible with each other and combined for the first time, result in catalytic decomposition of hydrogen peroxide, and releases active bleaching radicals that rapidly whiten teeth. The catalytic decomposition depends upon the concentration of H2O2, the concentration of the catalyst, temperature, and pH of the reacting solutions.
The multi-film delivery system also delivers additional benefits to consumers, yet provides convenience. Such additional benefits preferably include improved remineralization of the teeth, whitening of the teeth without pre-mixing or wasting of reagents and activators, better prevention of tooth sensitivity because anti-sensitivity ingredients can be separated from whitening compounds prior to usage and activated during application, and reduced wear time and enhanced level of comfort.
Illustrative of whitening strips containing peroxygen compounds for whitening teeth include U.S. Pat. Nos. 5,891,453, 7,785,572, 6,419,906, 6,893,629, 5,879,691, 6,949,240, 9,149,417 and 6,682,721.
U.S. Pat. No. 5,891,453 discloses a single-component transparent flexible strip material for delivering an adhesive tooth whitening substance. U.S. Pat. No. 5,879,691 discloses a single-component of transparent strip material having a flexural stiffness less than about 50 grams/centimeter and delivers a tooth whitening substance. The reasons for the apparent extreme similarities between U.S. Pat. Nos. 5,891,453 and 5,879,691 are not clear. However, to those skilled in tooth whitening strip technology, it is apparent that the claims of U.S. Pat. No. 5,879,691 are covered by the claims of U.S. Pat. No. 5,891,453.
U.S. Pat. No. 7,785,572 discloses a single-component dry adhesive device comprising a matrix adhesive layer containing a peroxide teeth whitening agent and a hydrophilic glassy polymer as a base polymer, and a backing layer. U.S. Pat. Nos. 6,419,906 discloses a single-component anhydrous water hydratable ethylene oxide polymer matrix film containing a solid peroxide whitening agent which when applied to stained teeth is hydrated by saliva and whitens teeth. U.S. Pat. No. 6,949,240 discloses a single-component tooth whitening strip carrying a tooth whitening peroxide active having a concentration greater than about 7.5% by weight and peroxide density less than about 1.3 mg/cm2. In comparison, the tooth whitening, desensitizing and remineralizing strip system described herein contains at least two film strips separate from each other prior to application.
U.S. Pat. No. 6,893,629 discloses a single-component, dissolvable, disintegrable film of flexible malleable polymer material having a tooth whitening substance dispersed within, when said film is adhered to the teeth, the film has a dissolution rate of about one hour during which to release its active tooth whitening substance. U.S. Pat. No. 9,149,417 discloses a single-component multi-layer dissolving tooth whitening strip comprises a solid dissolvable tooth contacting inner layer containing a tooth whitening active, and a dissolvable outer layer comprising a blend of polymers that dissolve after predetermined time and containing a tooth whitening active, and a bond forms between the tooth contacting inner layer and the outer layer by partially dissolving into each other during the film-casting process. U.S. Pat. No. 6,682,721 discloses a single-component multi-layer dry tooth whitening patch comprising a hydratable adhesive layer containing a stabilized peroxide tooth whitening agent and a peroxide-compatible hydrophilic glass polymer as a backing layer. In comparison, the multi-film tooth whitening, desensitizing and remineralizing strip system described herein contains a tooth contacting dissolvable adhesive film containing a peroxide activation complex and desensitizing agents and/or remineralizing agents and/or anti-inflammatory agents, and an undissolvable outer film strip containing a stabilized tooth whitening active and/or desensitizing agents and/or remineralizing agents and/or anti-inflammatory agents and fluid or liquid; the fluid or liquid in the outer film's composition dissolves the first tooth contacting orally dissolvable film and the first film's peroxide activation complex activates the peroxide compound on the second film and accelerate the tooth whitening action; the two said film strips are kept separate from each other until application.
It is well known that compliance in a therapeutic regimen has been shown to be directly related to the length of the therapy and the frequency of dosage. Hence, one object of this invention is to provide a system which can more rapidly whiten teeth by producing active bleaching species without undesirable long wear time (i.e.: for whitening strips with strong concentrations of 9.5% hydrogen peroxide or more: up to 2 hours a day, and requiring 7 days or more to show results; or for whitening strips with weaker concentrations of 7% hydrogen peroxide or less: the required frequency of usage of up to 28 days if worn for short period of 5 minutes per day). Another object of this invention is to provide with tooth whitening systems and compositions which can be used in the home by the consumer or can be used in the dental office. A further object of this invention is to provide desensitizing and/or remineralization effects during teeth whitening, with no additional wear time. Additionally, this invention can also be used to deliver effective in-situ remineralization by the reaction between phosphate source in the first orally dissolvable film and regeneration-source calcium salt on the second undissolvable film to generate hydroxyapatite, which reduces the likelihood of tooth sensitivity and tooth decay, and regenerates enamel.